When we recite the brachah over the Shabbos candles on eating matzah or on the arba minim we don’t mention anything about love. So why are the Kohanim singled out for being commanded to put “love” into their blessing?

Every morning before going to work a Jew performs a brief exercise. It’s a strength-training exercise meant to reinforce his love for others. It takes about five minutes and in Eretz Yisrael it’s part of the daily Shacharis service in shul. If performed daily according to the instructions it gives the heart muscles a wonderful massage keeping them strong and supple even when one goes out into the “real world.”
We all know what the “real world” is like. It’s like the Wild West where the lowest and pettiest human drives run rampant and personal interests set the tone threatening to wreak havoc on all that is humane. Who can say he has never felt that swelling ego that seeks only its own benefit even if it means trampling on others or humiliating them? The trampling can be anywhere: in industry in trade in the office and wherever people are struggling for parnassah status career goals or a seat on the subway.
But people who perform this daily exercise are protected. Their chances of developing hardening of their main arteries by selfishness meanness and cruelty are greatly reduced.
The exercise is actually a Torah commandment that appears in this week’s parshah. If we examine it carefully we’ll begin to see why it holds such great power to keep the Jewish heart fresh innocent and loving. Hashem commands Moshe:
“Speak to Aharon and his sons saying ‘So shall you bless the children of Israel: May Hashem bless you and keep you. May Hashem shine His Face upon you and be gracious to you. May Hashem lift His Face toward you and grant you peace’ ” (Bamidbar 6:22–26).
These are the words the Kohanim must say before the Jewish People. How is the rite performed? The Kohanim among the congregants leave the shul during the chazzan’s repetition of Shemoneh Esreh. They wash their hands and stand up on the duchan readying themselves to bless the people intently in the words prescribed by the Torah. They wait until they are called upon by the congregation to give their blessing. A congregant calls out “Kohanim!” and only then do they begin their brachah. This is the first point we should note as it will help us to understand what this exercise is all about.
As with any other mitzvah the Priestly Blessing is preceded by the recitation of a brachah on the mitzvah itself. That is before performing the mitzvah of blessing the people the Kohanim say a brachah with the familiar formula: “Blessed are You Hashem our G-d King of the Universe Who has sanctified us with the sanctity of Aharon and has commanded us to bless His people Israel…”
And here a word is added a word that is not found in any other brachah for a mitzvah. That word is “b’ahavah” — with love. “Blessed are You Hashem our G-d King of the Universe Who has sanctified us with the sanctity of Aharon and has commanded us to bless His people Israel with love.”
This expression is unique. When we recite the blessing on lighting Shabbos candles on eating matzah or on the arba minim we don’t mention anything about love.
What does this mean? That there is no obligation to perform any other mitzvah with love? And if so why is the mitzvah of Bircas Kohanim singled out to be performed with love? Furthermore where in the Torah does it specify that the Kohanim must bless the Children of Israel with love? Nothing about love appears in the pesukim we quoted above.
But precisely this added word is what opens the way to understanding the human psyche and the way our neshamos can connect to each other. Chazal who formulated the brachah on this mitzvah in Maseches Sotah (39) understood that love is the key to ensuring that the Priestly Blessing will be potent. They teach us “Rabi Yehoshua ben Levi said: One should not give a kos shel brachah [a cup of wine for Bircas Hamazon] to make blessings on to anyone but a tov ayin [one who looks kindly upon others without jealousy] as is said ‘A tov ayin will be blessed for he gave of his bread to the poor.’ Do not read it yevurach [will be blessed] but yevareich [will bless].”
After a meal it is customary to give the privilege of leading Bircas Hamazon to one of the men at the table. He recites the blessings over a cup of wine which he drinks from afterward. Rabi Yehoshua ben Levi says that this role should be given only to a person who is tov ayin a person with a “good eye” — that is a person who looks kindly and ungrudgingly upon others a person who is glad to see others enjoying blessings. The Maharsha applies Rabi Yehoshua’s principle to Bircas Kohanim explaining what the word b’ahavah comes to teach us: “Of necessity the [privilege of] blessing must be given only to a tov ayin because the blessing’s effect will be in accordance with the intent of the one reciting the blessing. And this is the meaning of ‘to bless His people Israel with love’ in Bircas Kohanim. That is with intent with an ayin tovah and with sincere desire” (Maharsha on the daf).
A blessing is only as effective as the one giving it wants it to be. A dynamic spiritual process invisible to the eye determines the quality of the brachah. This is not some mystical esoteric idea — it’s something we’ve probably all experienced in our own lives. We’ve all heard speeches that thrilled us that seemed to speak directly to us that moved us to act. Our hearts sensed the speaker’s sincerity felt that the words were coming from deep in his soul and the genuineness of those words had a corresponding effect deep in our soul. Yet if someone is merely giving a sales pitch or even a grand display of oratory but there’s no sincerity in his rhetoric we’re liable to be left cold. This is the secret of true communication with others.
So when the Torah commands the Kohanim to bless the people they are not just being asked to recite the prescribed words but to give a blessing from the heart. Unless one’s heart is awake and reaching out toward the other while giving a blessing it can’t form a conduit for that a downpour of Divine goodness. As the passage concludes “They shall place My Name upon the children of Israel and I shall bless them.”
Therefore the Kohanim must awaken in their hearts a true desire that the blessings articulated in the pesukim should be realized. In other words they must actually love the Jewish People. Only if the middah of ahavas Yisrael is second nature to them will they have the power day after day to bring an outpouring of Divine favor upon the congregation that turns to them with the request “Kohanim!” Then the people can bow their heads close their eyes drink in the blessings and answer “Amen!” Then the hearts of those channeling the blessings will be one with the hearts of the blessed open to each other. In the presence of this ayin tovah Hashem’s blessing pours down on the Jewish People and everyone in the congregation feels a sense of identification with his brethren.
The more we allow the meaning of Bircas Kohanim to imbue our hearts with ahavas Yisrael the more good we bring upon ourselves. Because one who has trained himself to be happy over his friend’s success and to erase jealousy from his heart lives a life of endless joy even if his own personal successes are relatively infrequent. Yet when he adds to them all the successes of his friends and acquaintances the simchah and goodwill he’ll experience becomes infinite. —

A sigh emitted because of a fellow’s pain breaks down all the barriers of the heavenly accusers. And when a person rejoices in the joy of his fellow and blesses him it is as dear to G?d and accepted by Him as the prayers of the High Priest in the Holy of Holies.
(Baal Shem Tov)